Electric switch



NOV. 17, 1931-. Wl Rl WALKER ELECTRIC SWITCH Filed Oct. 3l, 1924 Nw mwu. NN. QN .f/

!NVENTOR HRS ATTORNEY Patented Nov. 17, 1931.4

UNITED STATES PATENT OFFICE WARREN R. WAIR, 0F GREAT SKILLS, NEWASSIGNOR TO ELECTRIC VAPOR LAMP COMPANY, OF HOBOKEN, NEW JERSEY, -ACORPORATION vOIE' NEW JERSEY' ELECTRIC SWITCH Application led October31, 1924. Serial No. 746,945.

My present Vinvention relates to electric switches whichfarefpositivelyproof against the admission of gases and fine solid particles to themoving electric parts of the switch and which are especially suited foruse in gas houses, coal mines, grainelevators and other such places,where there is danger of ignition of explosive material by electricsparkings in the switching apparatus. The atmosphere of such places, attimes, is extremely sensitive to ignition agencies, es-

l pecially electric sparks.v

It is the object of my invention to provide a hermetically sealedelectric switch in which no sparking which is exposed to the atmospherecan occur vand which furthermore has a gas proof casing which completelyand' positively excludes the switch from the outer atmosphere. Thecasing has an operating mechanism connecting with said switch through agas tight opening in said casing.

It is an object of my invention to provide an electric switch of theliquid low type, having a sealed container of insulation material,usually glass, for the circuit making and breaking parts thereof, whichcontainer is supported on rigidly attached pivotal support members whichserve as terminal leads for the switch and which is surrounded by a gastight casing, the piyots of. said support members being provided withspring washers for keeping the' support members in constant electriccontact at their pivotal connections and having a handle or operatingmember connected withesaid switch or its support members co-axiallyfwith said pivots through a gas tight packing or stuffing box in saidcasing. Conductor leadsare run through said casing to the pivots fromthe outside. These leads are provided with vgas sealing means at theirpoints of passage through said casing.

'It is also an object of my invention to provide an electric switchwhich in its operation has long life and which has over a against eachother to maintain a non-spark; king contact therebetween.

t is a further object of my invention to provide an electric switchhaving a gas tight covering or casing and positively actuated operatingmeans extendingthrough said casing between which and the casing there ismaintained a permanent gas tight joint.

Other objects of my invention will appear from the specification anddrawings.

In the drawings:

Fig. 1 is a vertical cross-sectional view, throu h the switch casing,along the line 11, fg. 2, showing the switch parts end elevation.

Fig. 2 is a vertical cross-sectional view of the switch casing, alongthe line 2 2, Fig. 1, and showing the switch parts in front elevation.

In the drawings the base 10 supports the block 11 of insulating materialwhich in turn supports the spring clips 14 and 15 by means of the bolts16 and 17. The rigid metal strips 20 and 21, which are pivoted coaxiallyat their lower ends to the spring clips 14 and 15, respectively, ymakecontact at their respective upper ends with the respective terminals ofthe mercury switch tube 24 and serve as support means for said switch.Theswitch tube 24 is held tightly between two clips, 51 and 50, whichare inte al partsof the bars 21 and 20, the termina s of the tube beingforced between the clips, so that bars 20, 21, block rigidly together bymeans of said insulating block, or platform, 25 which serves as aprotecting means for said switch 24 and also serves for holdingthe-electrical connections thereto. The. joints between clips 14, 15 andthe side bars 20, 21 are made spark-proof by means of spring washers6,`inserted between theA pivot heads and nuts and the side bars. Circuitcontinuity is thus ensured in all angular positions of the bars 20, 21.To said strip 21 is fixed the member 27 which has a keyhole 28 formedtherein at a point which is on the line of the common axis of the pivotsof said bars 2() and 21 said keyhole 28 being formed square to admit ofthe insertion of a correspondingly shaped switch operating 1e- Ver orkey therein. From the character of this connection, it will be seen thatthe switch parts are positively actuated by the handle 48; i. e., acertain angular movement of the between said casing and said base andthe'4 packing 34 between the heads of said bolts 31, 31 and said case 30serve to make the joints at these points gas tight. The switch leads 37and 38Yconnected to bolts 16 and 17 respectively pass through the saidbase 10 at points within said casing 30 through openings 39, 39.Suitable packingmembers 40, 40 make a gas tight closure between saidopenings 39 and the respective leads which pass therethrough. In saidcasing 30 at a point opposite said key opening 28vis` formed an opening42 yin which there is mounted a stuffing box 43 through which theoperating-key 45 passes when it is positioned in said hole 28 for theoperation ofthe switch. The packing nut 46 serves to press the packing47 in box 43 about the stem of key 45 yfor making the slidable jointbetween said packing and the key stem 45 gas tight.

In the operation and use of the switch of my invention as for instancein a gas house or a grain elevator` where there is continued danger. ofignition of explosive gases or line particles of material the switchmechanism 1s mounted in a suitable position, with the joints between theleads 37 and 38 and the openings 39, 39 in base 10 suitably closed bypacking members 40, 40 to make such joints gas tight, the casing 30mounted on said base 10 about the switch mechanism by means of bolts 31,31, the joints between the base and the casing and between the casingand bolts being made gas tight by means of packings 33 and 34, 34respectivelyand the key 45 is inserted through stuffing box 43 into theopening 28 on the operating member 27 of. the s witch. The stuing box isthen made gasl tight by proper application of pressure on the packing 47by means of the nut 46. The switch is then operated without danger ofignition to an atmosphere of gas or fine inaterial dust particles bymeans of the handle 48 on key 45 or other suitable means which is usedto tilt the mercury switch 24 into the circuit making or circuitbreaking positions as is well known in the art.

Besides applica-tions to the control of circuits operatingin dangerouslyexplosive at` mospheres my invention has been found to' be successful asa satety switch mechanism in the control of track signal systems, whereconstant exposure tothe weather often causes ordinary switch apparatusto fail.

My invention provides double hermetical seals between the sparkproducing agencies of the switch and the outside, dangerously explosiveatmosphere in which the switch 1s to be used, as a circuit control.First there is the very perfect sealing of the switch tube itself\ andin addition the protection of its surrounding casing, in case the tubeshould be destroyed. I also consider the high insulation features of myinvention, introduced by the use of the two bars, or blocks 11 and 25,of high grade insulation, an important part of the design. It will benoted block 11 has only a small area of contact with its supportingcasing, and that it separates, or spaces, the lead conductors 37, 38 bya good sized gap, and keeps them away fromthe operating parts of theswitch mechanism. Block 25 is mounted at some distance from block 11,and securely holds the side bars 20, 21 rigidly, and at a safe distanceapart, at the same time providing for the easy renewal of the switchtube, if thatshould ever be necessary. These several advantages result,to

some extent from the arrangement of block,

11, as an insulated shelf, projecting from the back wall of the casing,and the carriage of block 25, by coaxial pivot members, welll insulatedrfrom each other, at some distance away from its supporting block 11,through the means of rigid side bars, diverging angularly from thesupport pivots.

What I claim as my invention is 1. An electric switch structurecomprising a mercury tube switch, a backing .member mounted to saidswitch by means of clip members each of which has a connection with a'respective terminal of the tube switch and an extension formed forpivotal support of the switch, pivotal support members for saidextensions, a gas tight casing about said switch and its pivotalsupport, leads connecting with said extensions at their respectivepivotal supports and extending through said casing by'gas tightpassages, and means for operating said switch which extends through saidcasing by a gas tight packing member.

- 2. An electric switch structure comprising a mercury tube switchhaving a sealed envelope, a mounting member lfor said envelope, strapsmounted to said envelope electrically connected to the leads thereof andmounted to said `mounting member, said straps having integral extensionsthereto formed for pivotal support of the switch, pivotal supportmembers for said-extensions, a member mounted to and offset from saidextensions and having a portion in axial alignment with said pivotalsuppoits, said axially aligned ortion being formed to engage a handle oroperating said switch, a gas tight casing about said switch and itspivotal support, and having formed therein an opening for the passage ofa handle 'for engaging said offset portion and a packing gland at saidopening.

IMI

3. A n electric switch structure comprising a mercury tube switch havinga sealed-,envelope, a mounting member for said envelope, straps mountedto said envelope electrically connected to the leads thereof and mountedto said mounting member, said straps having integral extensions thereto'formed for pivotal support of the switch, pivotal support members forsaid extensions, a member mounted to and offset from said extensions andhaving a portion in axial alignment with said pivotal supports, a; gastight casing about said switch and its ivotal support, handle meansextending tllirough said casing by a gas tight packing member andengaging said oli'set member at said axially aligned part for theactuation of the switch.

4. In a safety spark switch device, for use in explosive gas filledspaces, anvhermetically Y sealed casing inclosure provided with a shelfof insulation material, supported along a single edge of the shelf by aside wall of the casing, and serving as a high insulation platform topivotally support a block of insulation material, carrying a glassmercury tube switch element, relatively fixed with respect to saidblock, and actuating means whereby the position of said block on itspivotal support may be changed from the outside of said casing.

5. In a safety spark switch mechanism, for use in explosive gasatmospheres, a fixed switch part comprising an insulation base, and amovable switch part comprising a block of insulation material pivotedthereto by friction washer pivot means, designed to maintain continuityof electrical circuit between said fixed and movable switch parts andterminal clips on said block designed to detachably position a glassmercury tube switch element.

Signed at Hoboken in the county of Hudson and State of New Jersey this30th day Pof October, A. D. 1924:.

WARREN R. WALKER.

